Acaia scales

I sometimes use kitchen scales to ensure I dose ground coffee consistently into my portafilter. However, with a resolution of 1 g (typical of most kitchen scales), there could be 5 – 10% variability between shots. Not ideal for consistency! So, ever since I heard about 0.1 g resolution Acaia Pearl scale (see below), via it’s kickstarter campaign, I have been interested in getting one.

Now, I would have trouble justifying the Pearl’s expense purely to achieve a slightly more consistent dose – there are far cheaper scales available which would achieve that.

What really interested me was the super fast response (claimed to be 20 ms), and the ability to record measurements vs time via a bluetooth link to my mobile phone. Why? Purely for the fun of exploring how flowrate varies during an espresso pour!

It is established practice in the specialty coffee industry (and passionate amateurs) to experiment with espresso extraction variables (such as extraction time or preinfusion) by relating it to some property of the resulting espresso, such as volume, density or “brew ratio“.

This approach often results in significant, apparently mysterious, “random” error. I believe that looking at the dynamics of an espresso extraction (temperature, pressure and in particular flowrate) would shed some light on the source of this error, aid understanding and maybe even challenge some established dogma.

Being able to accurately measure the weight of an espresso pour over time would permit calculation of the flowrate over time!

Acaia recently released a new scale, the Acaia Lunar, which has a few new features aimed specifically at measuring espresso pours. The temptation just got a bit stronger…

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